code: def test_simple():
      R = (255 * np.random.rand(128, 256)).astype(np.uint16)
      R += np.arange(256, dtype=np.uint16)
      m0, m1 = mahotas.center_of_mass(R)
  
      assert 0 < m0 < 128
      assert 0 < m1 < 256
  
file_path: mahotas/mahotas/tests/test_center_of_mass.py
imports: import numpy
  from scipy import ndimage
  import mahotas.center_of_mass
label_desc: Use image node_id 5 for calling a global function with example usage: test_simple() without return types